Does Redis save long as Int?

I've got this exception.

java.lang.ClassCastException: class java.lang.Integer cannot be cast to class java.lang.Long (java.lang.Integer and java.lang.Long are in module java.base of loader 'bootstrap') 
2025-03-27 17:19:16     at com.example.ordermicroservice.service.RedisService.getBalance(RedisService.kt:45) ~[!/:0.0.1-SNAPSHOT]
2025-03-27 17:19:16     at com.example.ordermicroservice.service.AccountService$deposit$2$1.invokeSuspend(AccountService.kt:59) ~[!/:0.0.1-SNAPSHOT]
2025-03-27 17:19:16     at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) ~[kotlin-stdlib-1.9.25.jar!/:1.9.25-release-852]

With this code.

fun getBalance(accountNumber: String): Long {
    return numericRedisTemplate.opsForValue().get(accountNumber) ?: -1L
}

and my spring boot redis configuration.

@Bean
fun numericRedisTemplate(redisConnectionFactory: LettuceConnectionFactory): RedisTemplate<String, Long> {
    val template = RedisTemplate<String, Long>()

    template.connectionFactory = redisConnectionFactory
    template.keySerializer = StringRedisSerializer(Charsets.UTF_8)
    template.valueSerializer = GenericJackson2JsonRedisSerializer()
    template.hashKeySerializer = StringRedisSerializer(Charsets.UTF_8)
    template.hashValueSerializer = GenericJackson2JsonRedisSerializer()

    return template
}

I request value of Long type but there's ClassCastException. So does Redis save Long as Int?

numericRedisTemplate has an incorrect value serializer for its value type.
The value type is Long, but the serializer is for json.

So remove these lines from the numericRedisTemplate bean definition:

template.valueSerializer = GenericJackson2JsonRedisSerializer()
template.hashValueSerializer = GenericJackson2JsonRedisSerializer()

Or replace them by these

template.hashValueSerializer = GenericToStringSerializer(Long::class.java)
template.valueSerializer = GenericToStringSerializer(Long::class.java)